Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

GROWTH OF PENICILLIN-RESISTANT AND PENICILLIN-SENSITIVE STRAINS OF STAPHYLOCOCCUS AUREUS

1963 ◽  
Vol 9 (2) ◽  
pp. 179-186
Author(s):  
Wendall E. Allen ◽  
Ilda McVeigh
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Growth Phase ◽  
Growth Curves ◽  
Viable Cell ◽  
Fresh Medium ◽  
Logarithmic Growth Phase ◽  
Resistant Strains ◽  
Logarithmic Growth

Ten strains of naturally penicillin-resistant Staphylococcus aureus (obtained from patients), two in vitro derived resistant strains, and two sensitive strains, were grown at 37 C in Antibiotic Assay broth, and viable cell determinations were made at intervals. From these data, growth curves were plotted for each of the strains. The curves for the naturally penicillin-resistant and the sensitive strains are very similar. Little, if any, lag in growth of these strains occurred on transfer from maximum stationary-phase cultures to fresh medium. They grew at approximately the same rate during the logarithmic growth phase, which lasted for 3 to 4 hours; during the maximum stationary phase, about the same number of cells was present per milliliter in cultures of each of these strains. In contrast, the in vitro derived resistant strains underwent a lag of 2 to 6 hours on transfer to fresh medium and grew at a slower rate during the logarithmic growth phase. However, during the maximum stationary phase, which occurred after an incubation period of 24 to 32 hours, the cell titers were approximately the same as those of the naturally resistant and the sensitive strains. When grown in competition with either of the sensitive strains in Antibiotic Assay broth in the absence of penicillin, one of the naturally resistant strains persisted for 14 successive subcultures without any apparent change in ability to tolerate the antibiotic.

Regeneration of protoplasts in Saccharomyces

1972 ◽  
Vol 18 (11) ◽  
pp. 1773-1775 ◽  
Author(s):  
M. M. Shahin
Keyword(s):  
Growth Phase ◽  
Transition Phase ◽  
Protoplast Formation ◽  
Logarithmic Growth Phase ◽  
High Degree ◽  
Logarithmic Growth

Protoplasts prepared from cells of different stages within the logarithmic growth phase and from transition phase showed different degrees of colony-forming ability. The cells yielding higher frequency of protoplast formation also gave protoplast with a high degree of colony-forming ability.

scholarly journals THE FATE OF MITOCHONDRIA DURING AGING IN TETRAHYMENA PYRIFORMIS

1964 ◽  
Vol 20 (1) ◽  
pp. 113-129 ◽  
Author(s):  
Alfred M. Elliott ◽  
Il Jin Bak
Keyword(s):  
Growth Phase ◽  
Tetrahymena Pyriformis ◽  
Growth Cycle ◽  
Stationary Growth Phase ◽  
Stationary Growth ◽  
Logarithmic Growth Phase ◽  
Cytoplasmic Structures ◽  
Hydrolysis Of ◽  
Logarithmic Growth ◽  
Single Mitochondrion

During the growth cycle of Tetrahymena pyriformis the mitochondria undergo changes in position, number, and structure. Ciliates in the logarithmic growth phase possess elongated mitochondria which are aligned along the plasma membrane and are closely associated with the kinetosomes and kinetodesmata. Mitochondria appear to divide across the long axis at this time, resulting in two or more products. Throughout this phase of growth mitochondrial divisions keep pace with cytokinesis so that the population of mitochondria remains at essentially the minimal level. As the ciliates enter the stationary growth phase the mitochondria increase in number, become oval to spherical in shape, and some migrate into the cytoplasm. Intramitochondrial masses of various configurations appear at this time. Some of the mitochondria lying in the cytoplasm become incorporated into vacuoles. Within these vacuoles either a single mitochondrion appears or several mitochondria may be seen along with other cytoplasmic structures. Later in the stationary growth phase the contained mitochondria are dense and the tubules are more compact than normal. Various stages in disorganization of the mitochondria are observed in a single large vacuole. Cytochemical tests reveal the presence of acid phosphatase, suggesting that hydrolysis of the vacuolar contents occurs. Lipid droplets increase in number during the middle and late stationary phase of growth. These events are interpreted as being associated with the normal process of aging in T. pyriformis.

Ferrooxidans’s Isolation and Purification

2011 ◽  
Vol 356-360 ◽  
pp. 3-7
Author(s):  
Li Hua Lv ◽  
Jing Cheng Ren ◽  
Tian Hu Sun ◽  
Jian Qing Dai
Keyword(s):  
Growth Phase ◽  
Ph Value ◽  
Sodium Thiosulfate ◽  
Sulfur Oxidation ◽  
Optimum Growth ◽  
Logarithmic Growth Phase ◽  
Isolation And Purification ◽  
Optimum Growth Temperature ◽  
Mining Water ◽  
Logarithmic Growth

we take mining water from Liang Zou group undergroud 200 m. and cltured in 9K medium, sodium thiosulfate medium, sulfur (S0) medium. According to its conformation on the different mediums, we get ferrooxidans(T.f), and studying its ecological nature shows that the ferrooxidanis is acidophilic autotrophic bacteria and has ferrous iron and sulfur oxidation. Its optimum growth pH value is 2.0, optimum growth temperature is 30°C, 1.0 g/L of Fe2 + and 1 % S0 which can be used as the energy source are propitious to its growth. After UV mutagenesis, the strain which has been cold treated improve Fe2+ oxidation ability, at the same time, shorten the time enter to the logarithmic growth phase, the density of bacteria in lag growth phase increases from 6.8×107 cells/mL to 7.8×107 cells/mL, so increase bio-leaching capability.

scholarly journals Transcriptome analysis revealed growth phase-associated changes of a centenarian-originated probiotic Bifidobacterium animalis subsp. lactis A6

2021 ◽  
Author(s):  
Hui Wang ◽  
Jieran An ◽  
Chengfei Fan ◽  
Zhengyuan Zhai ◽  
Hongxing Zhang ◽  
...  
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Gene Cluster ◽  
Growth Phase ◽  
Differential Expression Analysis ◽  
Acid Tolerance ◽  
Glucose Consumption ◽  
Exponential Phase ◽  
Putative Gene ◽  
Bifidobacterium Animalis

Abstract Background The physiology and application characteristics of probiotics are closely associated with the growth phase. Bifidobacterium animalis subsp. lactis A6 is a promising probiotic strain isolated from the feces of a healthy centenarian in China. In this study, RNA-seq was carried out to investigate the metabolic mechanism between the exponential and the stationary phase in B. lactis A6. Results Differential expression analysis showed that a total of 810 genes were significantly changed in the stationary phase compared to the exponential phase, which consisted of 392 up-regulated and 418 down-regulated genes. The results showed that the transport and metabolism of cellobiose, xylooligosaccharides and raffinose were enhanced at the stationary phase, which expanded carbon source utilizing profile to confront with glucose consumption. Meanwhile, genes involved in NH3 production were up-regulated at the stationary phase to enhance acid tolerance during fermentation. In addition, peptidoglycan biosynthesis was significantly repressed, which is comparable with the decreased growth rate during the stationary phase. Remarkably, a putative gene cluster encoding Tad pili was up-regulated 6.5~12.1-fold, which is consistent with the significantly increased adhesion rate to mucin from 2.38–4.90% during the transition from the exponential phase to the stationary phase. Conclusions This study reported growth phase-associated changes of B. lactis A6 during fermentation, including expanded carbon source utilizing profile, enhanced acid tolerance, and up-regulated Tad pili gene cluster responsible for bacterial adhesion in the stationary phase. These findings provide a novel insight into the growth phase associated characteristics in B. lactis A6 and provide valuable information for further application in the food industry.

Hyaluronic acid modulates proliferation of mouse dermal fibroblasts in culture

1988 ◽  
Vol 90 (2) ◽  
pp. 265-273 ◽  
Author(s):  
M. Yoneda ◽  
M. Yamagata ◽  
S. Suzuki ◽  
K. Kimata
Keyword(s):  
Hyaluronic Acid ◽  
Cell Growth ◽  
Growth Phase ◽  
Primary Cultures ◽  
Mouse Skin ◽  
Acid Synthesis ◽  
Cell Number ◽  
Dermal Fibroblasts ◽  
Logarithmic Growth Phase ◽  
Logarithmic Growth

When the concentration of hyaluronic acid was monitored in primary cultures of mouse skin dermal fibroblasts, there was an increase in hyaluronic acid proportional to the increase in cell number during the logarithmic growth phase. The concentration reached the maximum value 2 days before the cells became confluent, and then decreased gradually. Hyaluronic acid added at 1 mg ml-1 during the logarithmic phase either promoted or inhibited cell growth, depending on the density of cells at the time when hyaluronic acid was added. Hyaluronic acid (1 mg ml-1) added to subconfluent or postconfluent cultures induced a transient DNA synthesis with a consequent increase (greater than 20%) in cell number. The effects appeared to be specific, since neither hyaluronic acid oligosaccharides nor some other types of glycosaminoglycan (chondroitin, chondroitin sulphates, heparan sulphates and heparin) had any similar effects. Dibutyryl adenosine 3′,5′-cyclic monophosphate (dbcAMP), at 1 mM, added to subconfluent or postconfluent cultures had promoting effects successively on hyaluronic acid synthesis and on cell growth. An increase in hyaluronic acid synthesis also occurred when dbcAMP was added to day 1 cultures in the logarithmic growth phase, but the effect on cell growth was reversed; there was an inhibition rather than a promotion. The pattern of cell density-dependent variation of the dbcAMP effect is quite similar to that observed with exogenously added hyaluronic acid. Therefore, we propose that hyaluronic acid added exogenously or supplied endogenously by increased synthesis may act as a modulator of mouse dermal fibroblast proliferation.

scholarly journals Investigation of growth kinetics and partial denitrification performance in strain Acinetobacter johnsonii under different environmental conditions

2019 ◽  
Vol 6 (12) ◽  
pp. 191275 ◽  
Author(s):  
Yang Zhang ◽  
Xiujie Wang ◽  
Weiqi Wang ◽  
Zhitao Sun ◽  
Jun Li
Keyword(s):  
Gene Expression ◽  
Growth Phase ◽  
Environmental Conditions ◽  
Sodium Acetate ◽  
Substrate Inhibition ◽  
Functional Genes ◽  
Logarithmic Growth Phase ◽  
Acinetobacter Johnsonii ◽  
Double Substrate ◽  
Logarithmic Growth

A denitrifying strain ZY04 with a high nitrite-accumulating rate was isolated and purified from activated sludge in a laboratory-scale A 2 /O reactor. The strain was characterized and identified as Acinetobacter johnsonii by 16S rDNA phylogenetic analysis. The sequences of the key functional genes ( napA , nirB , nirD ) involved in partial denitrification were amplified via polymerase chain reaction, which provided a basis for exploring gene expression. The effects of different environmental factors (C/N ratio, pH and temperature) on the partial denitrification performance and transcriptional levels of the functional genes during the logarithmic growth phase were investigated by batch experiments. The results showed that the partial denitrification performance was optimal when the C/N ratio was 5, the pH value was 6–8 and the temperature was 25°C. The gene expression during the logarithmic growth phase indicated the good performance of partial denitrification under different environmental conditions. All three functional genes exhibited the highest expression levels at 25°C. The results of inhibitory kinetics analysis revealed that three biokinetic models (Aiba, Edwards and Andrews) simulated the growth pattern of strain ZY04 inhibited by a single substrate (nitrate or sodium acetate) well. In the double-substrate inhibitory model, five models of nine combinations successfully fitted the growth characteristics of the strain affected by the double substrate of nitrate and sodium acetate. The relevant semi-saturation parameters and substrate inhibition parameters were obtained, and the correlation coefficient ( R 2 ) reached 98%.

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